Recording method for optical disc device

ABSTRACT

An optical disc device recording method, which includes determining whether or not a recording process that records information on a label surface of an optical disc has failed, detecting a recording failure position at which the recording process has failed when the determining step determines the recording process has failed, and resuming the recording process from the detected recording failure position.

This application is a continuation of co-pending application Ser. No.11/411,100, filed on Apr. 26, 2006, the entire contents of which arehereby incorporated by reference and for which priority is claimed under35 U.S.C. §120; and this application claims priority of Application No.10-2005-0034306 filed in Korea on Apr. 26, 2005 under 35 U.S.C. §119.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a recording method for an optical discdevice, and more particularly to a recording method which allows for theresumption of a recording process from a recording failure position onan optical disc such as a LightScribe disc having no tracking guidesignal.

2. Description of the Related Art

The LightScribe disc is an optical disc on which not only data can berecorded on a data surface, but also on which a label with a desireddesign can be printed on a label surface. A layout of the label surfaceof the LightScribe disc is shown in FIG. 1. As shown in FIG. 1, thelabel surface includes a label zone, a control feature zone, aclamping/logo zone and a center hole.

Turning now to FIG. 2, which illustrates a Control Feature Outer Ring(CFOR) area located in the control feature zone of the LightScribe disc.In FIG. 2, an index mark indicating the CFOR area and media informationsuch as a media ID are recorded in the CFOR area. As shown, the media IDis separately recorded in three fields which are discretely arranged inthe CFOR area.

Further, when the LightScribe disc is inserted into an optical discdevice capable of printing labels, the optical disc device locates theCFOR area in the disc by the index mark, reads the media informationfrom the CFOR area, and then performs a requested recording operation(i.e., label printing) on the label surface of the disc.

In addition, regarding the data side of the disc, wobble lands/groovesformed on the disc are used for performing a tracking servo controlprocess during a data recording process, and Absolute Time In Pre-groove(ATIP) information recorded in the wobble lands/grooves is used todetect the current position. The optical disc device performs thetracking servo control process in a feedback fashion using push-pullsignals generated from the lands/grooves, locates the current positionand gains access to a desired position based on the ATIP information.

However, because wobble lands/grooves are not formed on the label sideof the disc, it is not possible to perform a tracking servo controlprocess, nor is it possible to randomly access a portion of the disc.Thus, it is only possible to record a label on the disc sequentiallyfrom the inner to outer circular sections in a feedforward fashion.

Accordingly, when a recording or printing process on a label surfacefails due to unstable servo control, a disc medium problem, a bufferunder run, etc., the recording failure position cannot be located so thelabel recording process also fails.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to address theabove-noted and other problems.

Another object of the present invention is to provide an optical discrecording method that detects a position on the disc where a labelrecording process has failed and resumes the recording process at therecording failure position.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described herein, thepresent invention according to one aspect provides an optical discrecording method including determining whether or not a recordingprocess that records information on a label surface of an optical dischas failed, detecting a recording failure position at which therecording process has failed when the determining step determines therecording process has failed, and resuming the recording process fromthe detected recording failure position.

According to another aspect, the present invention provides a computerprogram product on at least one computer readable medium configured toexecute computer instructions, including a first computer codeconfigured to determine whether or not a recording process that recordsinformation on a label surface of an optical disc has failed, a secondcomputer code configured to detect a recording failure position at whichthe recording process has failed when the first computer code determinesthe recording process has failed, and a third computer code configuredto resume the recording process from the detected recording failureposition.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by illustration only, since various changes and modificationswithin the spirit and scope of the invention will become apparent tothose skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a layout of a label surface of a LightScribe disc;

FIG. 2 is an overview of a CFOR area located in a control feature zoneof the LightScribe disc;

FIG. 3 is a block diagram of an embodiment of an Optical Disc Device(ODD) in which a recording method in accordance with the presentinvention is implemented;

FIG. 4 is a flow chart of an embodiment of a recording method for anoptical disc device in accordance with the present invention;

FIG. 5 is an overview illustrating a detailed configuration of a controlfeature zone and an index mark pattern of the LightScribe disc;

FIG. 6 is a graph showing the relationship between a recording power andan Front Photo Detector Output (FPDO) signal; and

FIG. 7 illustrates a change in an Front Monitor Diode (FMD) signal dueto a recording process failure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of a recording method for an optical disc devicein accordance with the present invention will now be described in detailwith reference to the accompanying drawings.

FIG. 3 is a block diagram of an embodiment of an Optical Disc Device(ODD) in which a recording method in accordance with the presentinvention is implemented. As shown, the ODD includes an optical pickup20, a digital recording signal processor 30 a, a digital playback signalprocessor 30 b, a channel bit encoder 40, an optical drive 41, an R/Funit 50, a servo unit 60, a drive unit 61, a counter 12, a spokedetector 13, a memory 71, and a microprocessor 70. Also included are aspindle motor 11 and a sled motor 21.

The digital recording signal processor 30 a adds an error correctioncode (ECC) or the like to input digital data to convert the data into arecording format. The channel bit encoder 40 then converts the data intoa bitstream. Further, the optical drive 41 outputs a drive signalaccording to a signal received from the channel bit encoder 40, and theoptical pickup 20 records data according to the drive signal on anoptical disc 10 and also reads data from a recording surface of theoptical disc 10.

Further, the R/F unit 50 performs a filtering and wave shaping processon a signal output from the optical pickup 20 to thereby output a binarysignal. The drive unit 61 drives the sled motor 21 to move the opticalpickup 20 and the spindle motor M to rotate the optical disc 10. Inaddition, the counter 12 counts FG pulses produced as the spindle motor11 rotates, and the spoke detector 13 detects spokes formed on theoptical disc 10.

The servo unit 60 controls the operation of the drive unit 61 based onboth the rotational speed of the optical disc 10 and a servo signaloutput from the R/F unit 50. Further, the digital playback signalprocessor 30 b restores original data from the binary signal using itsinternal clock which is in phase with the binary signal received fromthe R/F unit 50. In addition, the memory 71 stores a variety of controldata and media information, and the microprocessor 70 applies therecording method according to the present invention to perform therecording process on the loaded optical disc 10.

Further, the sled motor 21 may be a step motor such as a craw-pole stepmotor. This type of step motor operates in a 2-phase excitation schemeand rotates by a desired step according to a combination of polaritiesof individual phase voltages. For example, one step corresponds to a1/20 rotation (i.e., rotation of 18°), and if a lead screw having apitch of 3 mm is provided, the above one step corresponds to arectilinear movement of 150 μm. In addition, the above-mentioned stepmotor preferably moves by a predetermined distance of 150 μm (e.g., 90tracks) for each step (=1 Kick).

In addition, the optical pickup 20 traverses the tracks on the disc.Further, to provide a greater sensitivity, an objective lens included inthe pickup 20 is also moved within the pickup 20 via an actuator. Forexample, the optical unit 20 may move in larger increments, and thenwithin each larger increment or step, the actuator moves the objectivelens in smaller increments. Thus, the microprocessor 70 determines theamount of track movement “Xs” of the optical pickup 20 from a drivingvalue of the sled motor 21 and the amount of track movement “Xa” of theobjective lens from a driving value of the actuator. The microprocessor70 also determines a position of a laser beam in the radial direction ofthe optical disc 10 from the two amounts of track movement Xs and Xa(i.e., the track position=Xs+Xa).

In addition, the microprocessor 70 stores in the memory 71 the amount oftrack movement of the optical pickup 20 per step (i.e., per kick pulse)and the movement of the objective lens included in the pickup 20corresponding to a specific driving value of the actuator. Thus, usingthese stored values, the microprocessor can detect a position on theoptical disc 10 in the radial direction at which a recording process hasfailed (and thus where the recording process is to be resumed).

Turning now to FIG. 4, which is a flow chart of an embodiment of arecording method for an optical disc device in accordance with thepresent invention. The elements in FIG. 3 will also be referred to inthis description.

In addition, in this embodiment, the inserted optical disc 10 is assumedto be a LightScribe disc including a label surface whose track cannot befollowed during recording because no tracking guide signal is produced.However, other discs may also be used.

As shown in FIG. 4, when the optical disc 10 is seated (Yes in S10), themicroprocessor 70 determines whether or not the seated surface of theoptical disc 10 is a label surface. If the microprocessor 70 determinesthe seated surface is a label surface (Yes in S20), the microprocessor70 moves the objective lens to a control feature zone of the opticaldisc 10 by applying appropriate driving values to the actuator of theoptical pickup 20 and the sled motor 21 through the servo unit 60 andthe drive unit 61, respectively.

For example, FIG. 5 shows a control feature zone and an index markpattern of the LightScribe disc. As shown in FIG. 5, the control featurezone includes a speed control features area, a control feature outerring area and a mirror area. The index mark formed in the CFOR area isprovided to make it easy to locate the CFOR area and to synchronize afirst spoke (Spoke 0). In addition, the first spoke (Spoke 0) starts atthe end position of the index mark, which is a reference position on thedisc in the circumferential direction.

Turning again to FIG. 4, the microprocessor 70 detects the index markfrom the index mark pattern of the CFOR area, synchronizes the Spoke 0based on this detection, and then reads media information of the CFORarea from the Spoke 0 (S21). The microprocessor 70 also stores the readinformation in the memory 71 and transmits the read information to ahost.

Further, the spoke detector 13 detects the spokes formed on the opticaldisc 10 when the optical disc 10 rotates, and the microprocessor 70counts the detected spokes. The microprocessor 70 also synchronizes theSpoke 0, starts counting spokes from this position and increases thespoke count value by one each time a spoke is detected by the spokedetector 13 (S22). In one example, 400 spokes (Spoke 0 to Spoke 399) areformed on the optical disc 10 along the circumferential direction.

In addition, at the end position of the index mark (or at the start ofthe Spoke 0), the microprocessor 70 controls the counter 12 to count FGpulses produced as the spindle motor 11 rotates (S22). In one example,20 FG pulses are produced when the optical disc 10 rotates once. Themicroprocessor 70 also detects a position on the optical disc 10 in thecircumferential direction through this count value.

Further, the spoke count value is more accurate than the FG pulse countvalue. Thus, the microprocessor 70 can approximately detect the positionon the optical disc 10 in the circumferential direction from the FGpulse count value, and then accurately detect the position on theoptical disc 10 in the circumferential direction from the spoke countvalue.

In addition, the microprocessor 70 continuously tracks the position onthe optical disc 10 in the circumferential direction through the countvalue (i.e., the spoke count value and/or the FG pulse count value)obtained with reference to the end position of the index mark. When alabel printing process is requested (Yes in S30), the microprocessor 70sets an appropriate recording power and records data transmitted fromthe host on a label zone of the label surface of the optical disc 10,while appropriately moving the optical pickup 20 and the objective lensby applying appropriate driving values to the step motor and theactuator (S31).

The microprocessor 70 also continuously stores the driving values of thestep motor and the actuator (or the amounts of movement of the stepmotor and the actuator according to the driving values), starting fromthe initial position of the recording process (e.g., the control featureouter ring area) (S31). When the recording process fails, the storeddriving values of the step motor and the actuator are used to detect aposition (e.g., a track position) in the radial direction of the opticaldisc 10 at which the recording process failed.

Further, when the optical disc 10 rotates during the recording process,the microprocessor 70 continuously tracks the position on the opticaldisc 10 in the circumferential direction based on the count valueobtained with reference to the end position of the index mark. Thus,during the recording process, the microprocessor 70 continuously checkswhether or not the recording process has failed (S32).

In addition, the optical pickup 20 includes a laser diode, which outputsa laser beam corresponding to a recording power voltage, and a FrontPhoto Detector (FPD), which detects a laser beam output from the laserdiode and outputs a Front Photo Detector Output (FPDO) signalcorresponding to the detected laser beam. Further, the microprocessor 70continuously monitors the FPDO signal during the recording process tocheck whether or not the recording process has failed.

Turning next to FIG. 6, which is a graph showing a relationship betweenthe recording power and the FPDO signal. As shown, the FPDO signal is ata predetermined reference level when no laser beam is output. Thus, inthis instance, the microprocessor 70 determines the recording processhas failed when the FPDO signal is detected at the reference level.

Another method of determining when the recording process has failed isto use Front Monitor Diode (FMD) signals. The FMD signals correspond tooutput voltages (i.e., FMD voltages) of cells A, B, C, and D, forexample, of a photodiode provided in the optical pickup 20 when a laserbeam having the set recording power is output. As shown in FIG. 7, theFMD signal shifts to a reference level when the recording process fails.Thus, in this instance, the microprocessor 70 determines the recordingprocess has failed when the FMD signal is detected at the referencelevel.

Returning to FIG. 4, when the microprocessor 70 determines the recordingprocess has failed (Yes in S40), the microprocessor 70 detects therecording failure position. That is, the microprocessor 70 detects botha position on the disc in the radial direction and the circumferentialdirection at which the recording process has failed. This process isperformed in the following manner.

The microprocessor 70 determines the number of driving values(specifically, the accumulated number of steps or kick pulses) appliedto the step motor from the initial position of the pickup 20 until thefailure of the recording process, and determines the driving valueapplied to the actuator at the moment when the recording process hasfailed. Based on the amount of track movement of the optical pickup 20per step or per kick pulse of the step motor and the amount of trackmovement of the objective lens corresponding to a specific driving valueof the actuator, which have been stored in the memory 71, themicroprocessor 70 calculates the amount of movement (Xs) of the opticalpickup 20 and the amount of movement (Xa) of the objective lens. Themicroprocessor 70 then detects the position on the disc in the radialdirection (e.g., the track position=Xs+Xa) at which the recordingprocess has failed (S41).

Once the radial position is detected, the microprocessor 70 determineswhether or not the optical disc 10 is tilted because the radial positionon the optical disc 10 may have a margin of error of a +1 or −1 trackdepending on the amount of the tilt. The microprocessor 70 alsodetermines whether or not the radial position at which the recordingprocess has failed has been accurately detected by detecting andcomparing signal levels of −1 and +1 tracks relative to the detectedradial position. This determination is based on the fact that, if thedetected radial position is accurate, the −1 track has been printed andthe +1 track has not been printed so the signal levels of the −1 and +1tracks are detected at different levels.

If the microprocessor 70 determines the radial position at which therecording process has failed has not been accurately detected, themicroprocessor 70 moves to a position −1 or +1 track away from thedetected radial position and detects and compares signal levels of −1and +1 tracks relative to the moved position to determine whether or notthe moved position is the radial position at which the recording processhas failed. The microprocessor 70 repeats this process until the radialposition is accurately located.

Further, as shown in FIG. 4, the microprocessor 70 also detects aposition on the optical disc 10 in the circumferential direction atwhich the recording process has failed, based on the number of FG pulsesand/or spokes, which is counted with reference to the end position ofthe index mark as the optical disc 10 rotates (S41). In the abovedescribed example, 400 spokes are counted and 20 FG pulses are countedwhen the optical disc 10 rotates once.

Thus, in this example, when the FG pulse count value is 10 and the spokecount value is 200, the microprocessor 70 detects that thecircumferential position at which the recording process has failed is aposition corresponding to 180 degrees in the rotational direction fromthe end position of the index mark. When the FG pulse count value is 15and the spoke count value is 300, the microprocessor 70 detects that thecircumferential position at which the recording process has failed is aposition (i.e., the end position of the index mark) corresponding to 270degrees in the rotational direction from the end position of the indexmark. Thereafter, the microprocessor 70 resumes the recording processfrom the detected recording failure position (e.g., from the radialcircumferential positions) at which the recording process has failed(S42).

The above embodiment may use another method for detecting the radialposition on the optical disc 10, in which the rate of generation (i.e.,the frequency) of the FG pulse is used to detect the radial position. Inmore detail, label printing of the LightScribe disc is performed in aConstant Linear Velocity (CLV) mode. In the CLV mode, the farther awayfrom the center of the optical disc 10, the lower the rotational speedor angular velocity is and the lower the rate of generation of the FGpulse is. Therefore, the microprocessor 70 detects the radial positionon the optical disc 10 from the rate of generation or frequency of theFG pulse. Likewise, the rate of detection of the spoke can also be usedto detect the radial position.

The microprocessor 70 can also detect the radial position on the opticaldisc 10 from the number of generated FG pulses from the FG pulse countvalue. Likewise, the microprocessor 70 can detect the radial position onthe optical disc 10 from the number of detected spokes from the spokecount value.

As is apparent from the above description, a recording method for anoptical disc in accordance with the present invention makes it possibleto accurately detect a position on a label surface of a disc at which arecording process has failed even though the disc provides no trackingguide signals. Thus, the recording process can be resumed from thedetected recording failure position, thereby achieving a stable labelprinting process.

This invention may be conveniently implemented using a conventionalgeneral purpose digital computer or microprocessor programmed accordingto the teachings of the present specification, as will be apparent tothose skilled in the computer art. Appropriate software coding canreadily be prepared by skilled programmers based on the teachings of thepresent disclosure, as will be apparent to those skilled in the softwareart. The invention may also be implemented by the preparation ofapplication specific integrated circuits whereby interconnecting anappropriate network of conventional computer circuits, as will bereadily apparent to those skilled in the art.

Any portion of the present invention implemented on a general purposedigital computer or microprocessor includes a computer program productwhich is a storage medium including instructions which can be used toprogram a computer to perform a process of the invention. The storagemedium can include, but is not limited to, any type of disk includingfloppy disk, optical disk, CD-ROMs, and magneto-optical disks, ROMs,RAMs, EPROMs, EEPROMs, magnetic or optical cards, or any type of mediasuitable for storing electronic instructions.

As the present invention may be embodied in several forms withoutdeparting from the spirit or essential characteristics thereof, itshould also be understood that the above-described embodiments are notlimited by any of the details of the foregoing description, unlessotherwise specified, but rather should be construed broadly within itsspirit and scope as defined in the appended claims, and therefore allchanges and modifications that fall within the metes and bounds of theclaims, or equivalence of such metes and bounds are therefore intendedto be embraced by the appended claims.

1. An optical disc recording method, comprising: when it is determinedthat a recording on a label surface of the optical disc has failed,calculating a failure position at which the recording has failed;confirming signal levels while at least one of inwardly and outwardlymoving an objective lens to positions around a radial position of thefailure position on a concentric circle of the label surface; detectingthe radial position of the failure position based on the confirmedsignal levels; and resuming the recording from the detected failureposition.
 2. The method according to claim 1, wherein the calculatingstep includes calculating a circumferential position of the failureposition based on at least one of a number of FG pulses and a number ofspokes counted from an end position of an index mark of the opticaldisc.
 3. The method according to claim 1, wherein the radial position ofthe failure position is calculated based on information about a positionof an optical pickup measured and stored from an initial position of therecording until the recording has failed, and information about aposition of the objective lens measured and stored at the moment whenthe recording has failed.
 4. The method according to claim 1, whereinthe radial position of the failure position is calculated based onstored driving values of an actuator and a sled motor after an initialposition of the recording.
 5. The method according to claim 4, whereinthe driving value of the sled motor is an accumulation of driving valuesapplied to the sled motor until the recording has failed after theinitial position of the recording, and the driving value of the actuatoris a value of a driving signal applied to the actuator at a positionwhen the recording has failed.
 6. The method according to claim 1,wherein the radial position of the failure position is calculated basedon at least one of information about FG pulses and information aboutdetected spokes.
 7. The method according to claim 6, wherein theinformation about the FG pulses is a rate at which an FG pulse isgenerated as the optical disc rotates at the moment when the recordinghas failed or a number of generated FG pulses until the recordingprocess has failed.
 8. The method according to claim 6, wherein theinformation about detected spokes is a rate at which a spoke is detectedas the optical disc rotates at the moment when the recording has failedor a number of detected spokes until the recording process has failed.9. The method according to claim 1, wherein whether the recording hasfailed is determined based on at least one of a Front Photo DetectorOutput (FPDO) signal and a Front Monitor Diode (FMD) signal.
 10. Anapparatus for recording information on a recording medium, the apparatuscomprising: an optical pickup, including an objective lens and anactuator, and configured to detect signals from or record data on therecording medium; and a controller configured to control the opticalpickup; wherein the controller is further configured to calculate afailure position at which a recording on a label surface of therecording medium has failed; confirm signal levels detected by theoptical pickup while controlling the optical pickup to at least one ofinwardly and outwardly move the objective lens to positions around aradial position of the failure position on a concentric circle of thelabel surface; detect the radial position of the failure position basedon the confirmed signal levels; and resume the recording from thedetected failure position.
 11. The apparatus according to claim 10,wherein the controller is configured to calculate a circumferentialposition of the failure position based on at least one of a number of FGpulses and a number of spokes counted from an end position of an indexmark of the recording medium.
 12. The apparatus according to claim 10,wherein the controller is configured to calculate the radial position ofthe failure position based on information about a position of theoptical pickup measured and stored from an initial position of therecording until the recording has failed, and information about aposition of the objective lens measured and stored at the moment whenthe recording has failed.
 13. The apparatus according to claim 10,wherein the controller is configured to calculate the radial position ofthe failure position based on stored driving values of the actuator anda sled motor after an initial position of the recording.
 14. Theapparatus according to claim 13, wherein the driving value of the sledmotor is an accumulation of driving values applied to the sled motoruntil the recording has failed after the initial position of therecording, and the driving value of the actuator is a value of a drivingsignal applied to the actuator at a position when the recording hasfailed.
 15. The apparatus according to claim 10, wherein the controlleris configured to calculate the radial position of the failure positionbased on at least one of a rate at which an FG pulse is generated as theoptical disc rotates and a rate at which a spoke is detected as theoptical disc rotates at the moment when the recording has failed. 16.The apparatus according to claim 10, wherein the controller isconfigured to calculate the radial position of the failure positionbased on at least one of a number of generated FG pulses and a number ofdetected spokes until the recording process has failed.
 17. Theapparatus according to claim 10, wherein the controller is configured todetermine whether the recording has failed based on at least one of aFront Photo Detector Output (FPDO) signal and a Front Monitor Diode(FMD) signal